Hearing impairment is a very common physical disability. One reason for poor hearing is reduced function in the inner ear. Age-related hearing loss is an example of reduced function of the inner ear.
Another reason for poor hearing is when the sound cannot reach the nerve cells of the inner ear. This is the case if a patient was born without external ear canals. In this case a conventional hearing aid with a mould in the ear canal opening is not a solution, however; if the inner ear is normal, sound conducted via the skull bone may give close to normal hearing. Accordingly, a bone-anchored hearing aid is primarily suited to people having conductive hearing losses, unilateral hearing losses and people with hearing losses who cannot wear in-the ear (ITE) or behind-the-ear (BTE) hearing aids.
Bone anchored hearing aids are vital for the rehabilitation of patients suffering from hearing losses for which traditional hearing aids are insufficient. A typical bone anchored hearing aid consists of an external hearing aid with a vibrating transducer that is connected to a skin-penetrating abutment through a coupling. The abutment may have an interconnection to a screw-shaped fixture anchored in the skull bone. Such fixture can be made of titanium and may be provided with a flange in order to prevent the fixture from being pushed through the skull bone when exposed to a sudden accidental impact.
The abutment penetrates the skin and the subcutaneous tissue in order to establish a direct coupling (direct bone conduction) from a hearing aid processor to the skull bone.
Some users with an abutment integrated in the skull experience skin reactions in the area around the abutment. Examples of inflammation or infection are often reported. Likewise, growth of granulation tissue and swelling of the tissue near the abutment can occur. In some case hypertrophy of tissue (including the skin) interferes with the sound processor and the user can be forced to stop using the device.
In difficult cases the problem of hypertrophy or swelling of tissue is solved by revision surgery and in the majority of cases by exchanging the abutment to a longer type in order to avoid contact to the surrounding skin.
Replacement of an abutment often requires the patient to be anaesthetized. Moreover, during abutment exchange there is risk of damage to the internal thread of the external hexagon of the fixture (implant). If the internal thread of the external hexagon of the fixture is damaged, a new surgery procedure is required in order to replace the damaged fixture.
Accordingly, it is desirable to have an alternative to exchanging the abutment in cases in which hypertrophy or swelling of tissue occur.
Therefore, the present disclosure provides an alternative to exchanging the abutment in cases in which swelling of tissue occur.